X-ray irradiation apparatus

ABSTRACT

An X-ray irradiation apparatus includes an enclosure and an X-ray beam system positioned within the enclosure for directing X-ray beams into an irradiation region. The X-ray beam system has more than one X-ray beam emitter for directing the X-ray beams into the irradiation region from different directions. Each X-ray beam emitter includes a vacuum chamber having a target window and an electron generator positioned within the vacuum chamber for generating electrons that are directed at the target window for forming X-rays which pass through the target window as an X-ray beam. The target window is supported by a support plate having a series of holes therethrough which allow passage of the electrons therethrough to reach the target window.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.10/102,509, filed Mar. 19, 2002, now U.S. Pat. No. 6,738,451 whichclaims the benefit of U.S. Provisional Application No. 60/277,322 filedon Mar. 20, 2001. The entire teachings of the above applications areincorporated herein by reference.

BACKGROUND

Many medical instruments are reusable and require sterilization betweenuses. Some of these instruments, for example, endoscopes andgastroscopes, are difficult to fully sterilize. Typically, suchinstruments are sterilized by hydrogen peroxide which is flushed throughthe interior as well as over the exterior of the instruments. This isnot only a time consuming process, taking about one hour, but often theinstruments have contaminated areas which the sterilizing process cannotsufficiently penetrate to fully sterilize such as biofilms of bacteria.In addition, the hydrogen peroxide is not able to kill all viruses.Another common sterilization agent is ethylene oxide which producessimilar results. Other methods of sterilization include irradiation withgamma radiation, but this method can take up to 24 hours with currentequipment.

SUMMARY

The present invention includes an apparatus that can be employed forsterilizing articles such as medical instruments more quickly andthoroughly than current methods. The present invention includes an X-raybeam emitter having vacuum chamber with a target window. An electrongenerator is positioned within the vacuum chamber for generatingelectrons that are directed at the target window for forming X-rays. TheX-rays pass through the target window in an X-ray beam.

In particular embodiments, the target window has a thickness whichsubstantially prevents the passage of electrons therethrough. Theelectrons and X-ray beam travel in substantially the same direction. TheX-ray beam is directed into an irradiation region for irradiatingarticles positioned therein. In some embodiments, the emitter is asterilization device where articles irradiated by the X-ray beam aresterilized.

The X-ray beam emitter can be part of an X-ray beam system in an X-rayirradiation apparatus which includes at least one X-ray beam emitter fordirecting at least one X-ray beam into an irradiation region. Inparticular embodiments, the X-ray beam system includes more than oneX-ray beam emitter for directing X-ray beams into the irradiation regionfrom different directions. In one embodiment, at least three X-ray beamemitters are positioned around the irradiation region thereby forming acentral irradiation chamber. In another embodiment, six X-ray beamemitters are positioned in a ring around the irradiation region and abutagainst each other. The X-ray beam system may include more than one ringof X-ray beam emitters which are joined together. In some embodiments,the apparatus is a sterilization apparatus where articles are positionedwithin the irradiation chamber for sterilization.

The present invention also includes a method of forming X-rays. Themethod includes providing a vacuum chamber having a target window. Anelectron generator is positioned within the vacuum chamber forgenerating electrons. The electrons are directed at the target window toform X-rays which pass through the target window in an X-ray beam. Thetarget window has a thickness which substantially prevents the passageof electrons therethrough. The electrons and the X-ray beam travel insubstantially the same direction.

The present invention also includes an X-ray irradiation apparatushaving an enclosure and an X-ray beam system positioned within theenclosure for directing X-ray beams into an irradiation region. TheX-ray beam system can have more than one X-ray beam emitter fordirecting the X-ray beams into the irradiation region from differentdirections. Each X-ray beam emitter includes a vacuum chamber having atarget window and an electron generator positioned within the vacuumchamber for generating electrons that are directed at the target windowfor forming X-rays which pass through the target window as an X-raybeam. The target window is supported by a support plate having a seriesof holes therethrough which allow passage of the electrons therethroughto reach the target window.

In particular embodiments, the enclosure can include a door forproviding access to the irradiation region. Each X-ray beam emitter caninclude a reflector surrounding the target window. The X-ray beam systemcan include at least three X-ray beam emitters positioned in a ringaround the irradiation region, thereby forming a central irradiationchamber. In one embodiment, the X-ray beam system includes eight X-raybeam emitters positioned in a ring around the irradiation region andabutting each other. The reflector of each X-ray beam emitter can abutthe reflector of an adjacent X-ray beam emitter. The target window ofthe X-ray beam emitter has a thickness which substantially prevents thepassage of electrons therethrough. The electrons and X-ray beam travelin substantially the same direction. The apparatus can be asterilization apparatus where articles are positioned within theirradiation chamber for sterilization.

The present invention also includes an X-ray emitter having a vacuumchamber with a target window and an electron generator positioned withinthe vacuum chamber for generating electrons that are directed at thetarget window for forming X-rays which pass through the target window inan X-ray beam. The target window is supported by a support plate havinga series of holes therethrough which allow passage of the electronstherethrough to reach the target window. A reflector surrounds thetarget window.

The present invention also includes a method of irradiating an articlewith an X-ray emitter including providing a vacuum chamber having atarget window. An electron generator is positioned within the vacuumchamber for generating electrons that are directed at the target windowfor forming X-rays which pass through the target window in an X-ray beamfor irradiating the article. The target window is supported by a supportplate having a series of holes therethrough which allow passage of theelectrons therethrough to reach the target window. The target window issurrounded with a reflector for reflecting X-rays towards the article.

When employed for sterilization purposes, the X-ray beams generated byembodiments of the present invention are able to deeply penetrate intothe articles being irradiated. Both surface and imbedded contaminantsare able to be irradiated for relatively quick and thoroughsterilization in comparison to traditional methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a simplified end view of an embodiment of the presentinvention X-ray beam irradiation apparatus.

FIG. 2 is a simplified perspective view of the X-ray beam irradiationapparatus of FIG. 1.

FIG. 3 is a side view of another embodiment of the present inventionX-ray beam irradiation apparatus.

FIG. 4 is an end sectional view of an embodiment of an X-ray beamemitter in accordance with the present invention.

FIG. 5 is a side sectional view of the X-ray beam emitter of FIG. 4.

FIG. 6 is a perspective view of another embodiment of an X-ray beamirradiation apparatus.

FIG. 7 is a perspective view of the X-ray beam irradiation apparatus ofFIG. 6 with a portion of the housing removed.

FIG. 8 is a front view of the X-ray beam irradiation apparatus of FIG. 6with a portion of the housing removed.

FIG. 9 is a perspective view of an embodiment of an X-ray beam emitterthat can be used in the X-ray beam irradiation apparatus of FIG. 6.

FIG. 10 is a schematic drawing of a centering fixture.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, X-ray beam irradiation apparatus 10 issuitable for sterilizing objects or articles, for example, medicalinstruments, tools or components. In the embodiment depicted in FIGS. 1and 2, X-ray beam irradiation apparatus 10 includes an x-ray beam systemhaving an X-ray irradiation unit 11 for irradiating articles 19. TheX-ray irradiation unit 11 of the embodiment depicted in FIGS. 1 and 2includes a series of X-ray beam emitters 12 each having a target window16 through which an X-ray beam 22 is generated. The X-ray beam emitters12 have angled side walls 14 which allow the X-ray beam emitters 12 tobe abutted against each other and joined together in a ring 10 asurrounding an irradiation region or chamber 20 so that the X-ray beamemitters 12 can direct the X-ray beams 22 radially inwardly intoirradiation chamber 20 from different directions. FIGS. 1 and 2 depictsix X-ray beam emitters 12 abutted against each other to form ahexagonal shaped irradiation chamber 20. The target windows 16 areclosely positioned to each other so that the X-ray beams 22 directedinto irradiation chamber 20 combine to provide substantially continuousradially inward X-ray beam coverage.

In use, articles 19 (FIG. 1) such as medical instruments requiringsterilization are typically positioned within irradiation chamber 20.Doors, such as those shown in FIG. 3, designated by reference numeral26, may be employed on opposite ends of irradiation chamber 20 toprovide shielding of the X-rays. Alternatively, elongated entrance andexit tunnels can be employed to provide shielding. Power to the X-raybeam emitters 12 is then provided so that X-ray beams 22 are directedinwardly into irradiation chamber 20. The X-ray beams 22 are able todisable, damage or kill bacteria, viruses, and organisms on the surfaceof the article 19. In addition, the X-ray beams 22 can penetrate intothe article 19 to sterilize regions deep within the article 19 as wellas penetrate and sterilize thick layers or regions of contamination.Instruments such as an endoscope may require a sterilization time ofabout a half hour at a low power of 5 kW per emitter 12 to achievethorough sterilization. This is about half the time in comparison to theone hour typically required when sterilizing with hydrogen peroxide.Even over such an amount of time, instruments sterilized by hydrogenperoxide are not as thoroughly sterilized as in the present invention.

Although six X-ray beam emitters 12 are shown in FIGS. 1 and 2 to formX-ray irradiation unit 11, it is understood that any number of X-raybeam emitters 12 can be employed. When three emitters 12 are employed,irradiation chamber 20 can be triangular in shape, with four emitters12, square, and with five and above, polygonal. When multiple emitters12 are employed, irradiation chamber 20 can also have configurationsthat are wide and flat, or convoluted, depending upon the situation. Insome cases, X-ray irradiation unit 11 may only need one or two X-raybeam emitters 12. In such cases, reflectors for reflecting X-rays can beused in combination with the X-ray beam emitters 12. Additionally,although x-ray emitters 12 have been shown to be joined together in aring 10 a, alternatively, one or more X-ray emitters 12 may bepositioned for providing X-ray beams that are not in a substantiallycontinuous circle, for example, from one or two directions. When twoX-ray beam emitters 12 are employed, the emitters 12 can be arranged inopposed fashion.

Referring to FIG. 3, X-ray beam irradiation apparatus 24 is employedwhen sterilizing articles 19 that are too long to fit within apparatus10. X-ray beam irradiation apparatus 24 includes an X-ray beam systemhaving more than one X-ray irradiation unit 11 joined together. In oneembodiment, each X-ray irradiation unit 11 includes a ring 10 a of X-raybeam emitters 12 similar to that depicted in FIGS. 1 and 2. The rings 10a are abutted against each other and joined together so that theirradiation chambers 20 of each ring 10 a join together collectively toform one long irradiation region or chamber 28. Three X-ray irradiationunits 11 are shown abutted together, however, less than three or morethan three units 11 can be joined together. Typically, X-ray beamirradiation apparatus 24 includes doors 26 to provide shielding of theX-rays. Although instruments are typically positioned in a stationarymanner within irradiation chamber 28, alternatively, a conveyor systemcan be employed to slowly move articles 19 through irradiation chamber28. The conveyor system may include conveyor belts and/or rollers. Whena conveyor system is employed, entrance and exit tunnels may bedesirable to provide shielding.

It is understood that X-ray irradiation apparatus 24 can have X-rayirradiation units 11 of configurations that are different than ring 10 asuch as discussed above. In addition, some embodiments of theirradiation units 11 can include mechanisms for moving one or moreemitters 12 over or around an article 19 for providing X-ray irradiationwith a minimum number of emitters 12. In one embodiment, a ring 10 a istranslated longitudinally along article 19. In another embodiment, anemitter 12 is rotated around article 19 and can also be translatedlongitudinally over article 19. In configurations where an emitter 12 isrotated around article 19, employing more than one emitter 12 can reducethe amount of rotation required. For example, if two emitters 12 areemployed positioned in opposed fashion, the emitters 12 can be rotatedonly 180° around article 19.

In addition to sterilizing medical instruments, tools or components,X-ray beam irradiation apparatuses 10 and 24 can be employed tosterilize implantable devices or components such as artificial joints,pins, plates, pumps, pacemakers, etc. Furthermore, a wide variety ofobjects or articles 19 can be sterilized, including items for use in asterile room or environment. In some instances, it may be desirable tosterilize substances such as powders, liquids or food items. Referringto FIG. 3, X-ray beam irradiation apparatus 24 can be employed as asterilizing entrance for articles 19 entering a sterile environmentwhere one end of apparatus 24 is connected to the sterile environment,typically, extending through a wall thereof. One door 26 allows articles19 to be inserted into apparatus 24 from the exterior for sterilization.The other door 26 allows removal of the sterilized article 19 fromapparatus 24 into the sterile environment.

Referring to FIGS. 4 and 5, X-ray beam emitter 12 in one embodimentincludes a hermetically sealed vacuum chamber 30 having a rectangulartarget window 16 positioned at one end thereof. An electron generator 32is positioned within the interior 30 a of vacuum chamber 30 forgenerating electrons e⁻ which are accelerated towards the target window16 for forming X-rays. The target window 16 typically consists of a thinmetallic foil that has a thickness sufficient to substantially preventthe passage of electrons e⁻ through while allowing passage of X-rays.The target window 16 is supported by a support plate 38 having a seriesof holes 38 a therethrough which allow the electrons e⁻ to reach targetwindow 16. In some embodiments, outwardly angled holes 38 b may beincluded at the far ends of support plate 38 (FIG. 5) to direct moreelectrons e⁻ to the ends of target window 16. The target window 16 issealed to support plate 38 by bonding under heat and pressure, butalternatively could be brazed or welded. In one embodiment, the targetwindow 16 can be 12 inches long so that irradiation chamber 20 is about12 inches long. When X-ray beam emitters 12 are to be abutted againsteach other in a ring such as ring 10 a (FIG. 1), the emitters 12 canhave angled sides 14 which extend towards and near the longer sides ofthe target window 16 (FIG. 4). Sides 14 are angled at about 60° when sixemitters 12 are abutted together, however, the angle of sides 14 candiffer depending upon the number of emitters 12 joined together. In someirradiation chamber 20 configurations, the angled sides 14 can beomitted, for example, in some rectangular configurations. A tube may beextended from vacuum chamber 30 and connected to a vacuum pump forevacuating vacuum chamber 30 which is then sealed off to hermeticallyseal vacuum chamber 30.

The electron generator 32 has a filament housing 34 which in oneembodiment is disc shaped and has a series of openings in the bottom 34a. Tungsten filaments 36 are positioned within housing 34 for generatingthe electrons e⁻. Filament housing 34 is electrically connected to ahigh voltage supply by tubular conductor 40 a and cable 18. Commonranges are 100–300 kV with 125 kV being typical. In some applications,voltages 100 kV and above 300 kV may be desirable. Target window 16 iselectrically grounded to impose a high voltage potential betweenfilament housing 34 and target window 16. Filaments 36 are providedpower by a filament power supply electrically connected to cable 18 andare electrically connected at one end to a conductor 42 extending withinthe interior of filament housing 34, and are electrically connected atthe other end to a conductor 40 b extending from cable 18. The upperportions of conductor 40 a is embedded within insulating materials 44.

In use, the filaments 36 are provided with power to heat filaments 36 toabout 3400° F. to 4200° F. which causes free electrons e⁻ to form onfilaments 36. The high voltage potential imposed between the filamenthousing 34 and target window 16 causes the free electrons e⁻ onfilaments 36 to accelerate from the filaments 36 in a beam throughopenings in the bottom 34 a of filament housing 34 to target window 16.The target window 16 is typically a thin foil of gold, titanium ortungsten about 3 microns thick which substantially blocks or preventsthe passage of electrons e⁻ therethrough, but, alternatively, may beformed of titanium with a layer of gold thereon, or be formed of goldwith copper or silver. Typically, metals with a high Z number and goodthermal conductivity are preferred, but it is understood that thematerial of target window 16 can vary depending upon the application athand. For example, materials and combinations other than those describedabove can be used. The electrons e⁻ striking the target window 16typically do not pass through but instead form X-rays which exit oremerge from the target window 16 in an X-ray beam 22 and continue totravel substantially in the same forward direction as the electrons e⁻were traveling. In other words, the beam of electrons e⁻ is transformedor changed by target window 16 into the X-ray beam 22 resulting in acontinuous two-part or stage beam where the first stage is formed by thebeam of electrons e⁻ and the second stage is formed by the X-ray beam22. The X-ray beam 22 exits target window 16 with substantially the sameoutline as target window 16. The production of X-rays in this mannerprovides a relatively efficient broad X-ray beam 22 because both theelectrons e⁻ and the X-ray beam 22 are traveling in the same forwarddirection. The beam of electrons e⁻ and the X-ray beam 22 are shown tobe perpendicular or substantially perpendicular to target window 16. Insome situations, electrons e⁻ might strike target window 16 at an angle.

In some embodiments, target window 16 may be configured to allow someelectrons e⁻ to pass through to provide a mix of electrons e⁻ andX-rays. In further embodiments, the target window 16 can be replaced byan electron beam exit window which allows the electrons e⁻ to exit theemitters 12 in an electron beam. In such a case, the electrons e⁻ strikethe surface of the article to be sterilized thereby sterilizing thesurface and, at the same time, creating X-rays which sterilize theinterior. Such an embodiment can be used to sterilize or decontaminateany type of suitable equipment. The target window 16 can be configuredto suit particular arrangements, and can be of shapes other thanrectangular.

Referring to FIGS. 6–8, X-ray beam irradiation apparatus 50 is anotherembodiment of an X-ray beam irradiation apparatus. Apparatus 50 includesan enclosure 52 which houses a ring 58 of X-ray beam emitters 60.Enclosure 52 is made of materials that provide shielding from X-raybeams 22 and can include at least one door 26 for providing access tothe irradiation chamber 56.

The X-ray beam emitters 60 each have a reflector 54 surrounding thetarget window 16 of the vacuum chamber 62 for reflecting X-ray beams 22that strike reflector 54 back toward the article 19 that is beingirradiated. The reflectors 54 can be joined together or abut each other,as shown. The X-ray beam emitter 60 is similar to X-ray beam emitter 12but can be laterally elongate as shown to provide an elongaterectangular target window 16. In one embodiment, the target window 16can be 16 inches long. By appropriately sizing the reflectors 54, thereflectors 54 can abut against each other so that the X-ray beamemitters 60 can be arranged in an enclosed ring 58, while at the sametime the vacuum chambers 62 are spaced apart from each other a largeenough distance so that the sides of the vacuum chambers 62 do not haveto be angled such as shown in FIGS. 1, 2 and 4. In some embodiments, thesupport plate 38 can be configured to serve as the reflector 54. Inother embodiments, the reflector 54 can be a separate component that isfitted around the target window 16. FIG. 9 depicts one embodiment ofX-ray emitter 60 where the support plate 38 protrudes from the vacuumchamber 62 and allows the reflector 54 to be fitted around the supportplate 38.

In use, the door 26 is opened and the article 19 to be irradiated isplaced within the irradiation chamber 56. Once the article 19 is placedwithin the irradiation chamber 56, and door 26 closed, the X-ray beamemitters 60 can be turned on to irradiate the article 19 with X-raybeams 22. X-ray beams 22 that pass by the article 19 can be reflectedback into the central region of the irradiation chamber 56 by thereflectors 54 surrounding the target windows 16. An X-ray sensor 64within the irradiation chamber 56 can monitor the amount of radiationdirected towards the article 19 and when the desired level is sensed,turn the X-ray beam emitters 60 off. With some configurations of thearticle 19, the article 19 can be held by or placed within a centeringfixture 66 (FIG. 10) such as a basket which is placed within theirradiation chamber 56. The centering fixture 66 is configured to allowpassage of most of the X-ray beams 22 to the article 19. In someembodiments, the centering fixture 66 can also rotate the article 19within the irradiation chamber 56. For small articles 19, the centeringfixture 66 can include centering members 68 for centering the article19.

In other embodiments of apparatus 50, the axial ends of apparatus 50 canbe configured to allow the passage of an article 19 that is continuouslymoving through the apparatus 50, such as a continuously moving profile.In such a situation, appropriate shielding is employed. In addition, theemitters 60 can be rotatable about the article 19. Furthermore, theaxial ends of the apparatus 50 can be configured for centering thearticle 19.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims. For example, features of the variousembodiments discussed above may be combined with each other or omitted.It is understood that the configuration, shape, dimensions, size andpower of X-ray emitters 12 and 60 can be varied depending upon theapplication at hand as well as the shape of the target window 16.Multiple emitters 12 and 60 may be positioned side by side forgenerating an X-ray beam 22 from one direction, or positioned inopposing directions for generating X-ray beams 22 from two directions.In some configurations, the X-ray beams 22 from emitters 12 and 60 arenot joined in a continuous manner. In addition, X-ray emitters 12 and 60and apparatuses 10, 24 and 50 may be employed to irradiate or sterilizeany desired article, or may be used for other typical purposes, such astaking an X-ray of a patient or curing coatings.

1. An X-ray irradiation apparatus comprising: an enclosure; and an X-raybeam system positioned within the enclosure for directing X-ray beamsinto an irradiation region, the X-ray beam system comprising more thanone X-ray beam emitter for directing the X-ray beams into theirradiation region from different directions, each X-ray beam emittercomprising: a vacuum chamber having a target window; and an electrongenerator positioned within the vacuum chamber for generating electronsthat are directed at the target window for forming X-rays which passthrough the target window as an X-ray beam, the target window beingsupported by a support plate having a series of holes therethrough whichallow passage of the electrons therethrough to reach the target window.2. The apparatus of claim 1 in which the enclosure includes a door forproviding access to the irradiation region.
 3. The apparatus of claim 2in which each X-ray beam emitter includes a reflector surrounding thetarget window.
 4. The apparatus of claim 3 in which the X-ray beamsystem comprises at least three X-ray beam emitters positioned in a ringaround the irradiation region, thereby forming a central irradiationchamber.
 5. The apparatus of claim 4 in which the X-ray beam systemcomprises eight X-ray beam emitters positioned in a ring around theirradiation region and abutting each other.
 6. The apparatus of claim 5in which the reflector of each X-ray beam emitter abuts the reflector ofan adjacent X-ray beam emitter.
 7. The apparatus of claim 1 in which thetarget window of the X-ray beam emitter has a thickness whichsubstantially prevents the passage of electrons therethrough.
 8. Theapparatus of claim 7 in which the electrons and X-ray beam travel insubstantially the same direction.
 9. The apparatus of claim 1 in whichthe apparatus is a sterilization apparatus where articles are positionedwithin the irradiation chamber for sterilization.
 10. An X-ray emittercomprising: a vacuum chamber having a target window; an electrongenerator positioned within the vacuum chamber for generating electronsthat are directed at the target window for forming X-rays which passthrough the target window in an X-ray beam, the target window beingsupported by a support plate having a series of holes therethrough whichallow passage of the electrons therethrough to reach the target window;and a reflector surrounding the target window.
 11. A method ofirradiating an article with an X-ray irradiation apparatus comprising:providing an enclosure; and positioning an X-ray beam system within theenclosure for directing X-ray beams into an irradiation region forirradiating the article, the X-ray beam system comprising more than oneX-ray beam emitter for directing the X-ray beams into the irradiationregion from different directions, each X-ray beam emitter comprising: avacuum chamber having a target window; and an electron generatorpositioned within the vacuum chamber for generating electrons that aredirected at the target window for forming X-rays which pass through thetarget window as an X-ray beam, the target window being supported by asupport plate having a series of holes therethrough which allow passageof the electrons therethrough to reach the target window.
 12. The methodof claim 11 further comprising providing a door for providing access tothe irradiation region.
 13. The method of claim 12 further comprisingsurrounding the target window of each X-ray beam emitter with areflector.
 14. The method of claim 13 further comprising forming theX-ray beam system with at least three X-ray beam emitters positioned ina ring around the irradiation region, thereby forming a centralirradiation chamber.
 15. The method of claim 14 further comprisingforming the X-ray beam system with eight X-ray beam emitters positionedin a ring around the irradiation region and abutting each other.
 16. Themethod of claim 15 further comprising positioning the reflector of eachX-ray beam emitter to abut the reflector of an adjacent X-ray beamemitter.
 17. The method of claim 11 further comprising forming thetarget window of the X-ray beam emitter with a thickness whichsubstantially prevents the passage of electrons therethrough.
 18. Themethod of claim 17 further comprising directing the electrons and X-raybeam in substantially the same direction.
 19. The method of claim 11further comprising positioning the articles within the irradiationchamber for sterilization.
 20. A method of irradiating an article withan X-ray emitter comprising: providing a vacuum chamber having a targetwindow; positioning an electron generator within the vacuum chamber forgenerating electrons that are directed at the target window in an X-raybeam for irradiating the article, the target window being supported by asupport plate having a series of holes therethrough which allow passageof the electrons therethrough to reach the target window; andsurrounding the target window with a reflector for reflecting X-raystowards the article.